The invention generally relates to an instrumented packer.
An oilfield well may have several production zones. These zones are established by one or more wellbores (of the well) that extend through one or more subterranean formations. Different zones may need to be treated over the lifetime of the well.
For example, a well treatment may be needed to selectively block or seal off production from a particular zone. In this manner, production from each zone is not always the same, as the compositions of the fluids produced by the zones typically vary. For example, some of the zones may produce an unacceptable level of water, and thus, it may be desirable to seal off these zones from the well. As another example, some of the zones may produce unacceptable levels of contaminants, and thus, it may be desirable to also block the communication of fluids from these zones. The quality of production from a particular zone may vary over the course of the well's lifetime. For example, over time, a zone may transition from producing well fluid of an acceptable quality to producing too much water or producing well fluid having an unacceptably high level of contaminants.
Thus, at some point, either before the initial installation of production equipment or at a later time, corrective action may have to be performed to seal off a particular zone in a well. One type of corrective action involves a technique that is referred to in the industry as a “squeeze job.” In a squeeze job, any production tubing that is present in the well is first removed from the affected zone. Subsequently, the zone is isolated using temporary packers. This isolation involves sealing off the area inside the casing string or inside the wellbore, depending on whether the well is cased. A mixture called a cement slurry is then pumped down through a tube into the isolated zone and hardens into a cement to seal off the zone.
In the squeeze job, the cement slurry may be directed into perforation tunnels of the zone. In other applications, the cement may fill gravel packing of the zone. In this manner, the gravel packing is used in some wells to filter sand in an unconsolidated formation while allowing the oil to flow through. However, the corresponding production zone may be invaded by brine and thus, it may become necessary to plug the gravel packing by cementing through the gravel.
Well treatments also exist to enhance the production from a particular zone. For example, it may be desirable to introduce acid in a zone, in an operation called “acidizing.” The introduced acid increases the productivity of the zone. However, when acidizing, it may be necessary to isolate the zone in which acid is introduced, because if the acid reaches a particular water-producing zone, water production from that zone may be undesirably enhanced. Thus, for the acidizing operation, it is also desirable to isolate the zone in which the operation is being performed.
In all of the above-described operations, an estimation typically is made of the volume of fluid (i.e., the cement slurry, acidizing fluid, or other chemical) that is needed to complete the well treatment operation. For example, in a cement squeeze operation, an estimation of the volume of cement slurry needed to isolate a particular zone is made. However, it is often difficult to ascertain the volume capacity of the zone into which the fluid is being introduced, and this difficulty may present challenges in effectively performing the operation. For example, if not enough cement slurry is used in a cement squeeze operation, then the targeted zone may not be properly isolated. However, if too much cement slurry is communicated into the well, production from an adjacent zone may be advertently blocked. As another example, if too much acidizing fluid is introduced into the targeted zone, the acidizing fluid may migrate into an adjacent water producing zone and enhance the water production from that zone.
Thus, there is a continuing need for an arrangement and/or technique to address one or more of the problems that are stated above as well as possibly address other problems not stated above.